<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<title>Document</title>
	<style>
		.box {
			width: 200px;
			height: 200px;
			background-color: green;
			/* 分别设置过渡属性 */
			/* transition-property: width, height; */
			/* 分别设置过渡持续时间 */
			/* transition-duration: 1s, 2s; */
			/* 让所有能过渡的属性发生过渡 */
			/* transition-property: all; */
			/* 过度持续时间 */
			/* transition-duration: 1s; */
			/* 过渡简写 */
			transition: 1s all;
		}

		.box:hover {
			width: 400px;
			height: 400px;
		}
	</style>
</head>
<body>
	<div class="box"></div>
</body>
</html>